Took me a while to wrap my little brain around it all too -- working with the negative space and positive space measurements. (Or is the other way around? ;-))
I had both shoes and socks off in order to count on my fingers & toes at the Yamaha parts counter, just trying to cipher out the shim selections. Lucky for me they were patient and understanding, and left me the whole box of shims to pick from. The other issue I had was the feeler gage - one blade is labeled 6, and another is labeled 9. Kinda hard to tell which is which on the fly when shuffling through a slew of 'em. I finally got the sharpie out and labeled them "six" & "nine"
